Featured Research

from universities, journals, and other organizations

New Type Of Massive Stellar Death

Date:
December 24, 2006
Source:
University of Copenhagen
Summary:
So far we have thought that the signature of the death of a massive star was an energetic explosion called a "supernova." New observations show that this is not always the case. On the contrary, a team led by Danish researchers has now discovered that some massive stars die by collapsing into a black hole returning very little material into the interstellar medium. The new discovery is published in Nature.

Stars die when they have exhausted the fuel in their centres and until now it has been believed, that stars could only die in two ways -- one way for the smaller and medium size stars and one way for the very massive stars. Our sun is a middle size star. When stars that are smaller than our sun or up to 8 times more massive than the sun die, they expel the outer layers and leave behind a white dwarf in the centre

Stars with a mass more than 8 times that of our sun die violently in energetic supernova explosions expelling several solar masses of chemically enriched material into the interstellar medium leaving behind either neutron stars or black holes in the centre. In this way the interstellar medium becomes more and more enriched in elements such as Oxygen and Carbon, that are essential for life.

The new discovery

In May and June of this year, two long-duration Gamma-ray bursts (GRBs) were detected by the NASA satellite Swift. GRBs are power-full bursts of gamma-rays coming from far away. There has been a tremendous progress in the study of this during the last 10 years, and it has been found that the long-duration GRBs (these have duration longer than 2 seconds) are caused by the deaths of massive stars.

A team of astrophysics from Dark Cosmology Centre (DARK) at the Niels Bohr Institute, University of Copenhagen monitored the two bursts intensively during June, July, August and September 2006. The remarkable conclusion from this monitoring was that there were no supernovae associated with these two Gamma-ray bursts.

Conclusion of this research

There are two possible conclusions: 1) that these GRBs were not caused by massive stars, or 2) that they were caused by massive stars that did not cause associated supernova explosions. Focusing on the May burst, where the team have the strongest evidence, the team has obtained deep images in very good observing conditions and spectroscopy as well. This allowed the team to localise exactly where in the host galaxy the burst occurred.

The host galaxy turns out to be a small spiral galaxy, and the burst occurred in a compact star-forming region in one of the spiral arms of the galaxy. This is strong evidence that the star(s) that made the GRB were massive, as massive stars due to their short lifetimes (few million years) are only found in star-forming regions.

Some massive stars simply collapse

The implications of this discovery are therefore this: Where as we up till know thought that massive stars died in supernova explosions expelling large materials of enriched material into the interstellar medium, it seems that this is not always the case.

The theoretical idea is that some massive stars simply collapse under the formation of a black hole (either directly as water running out of the sink, or in an indirect way where some material gets expelled, but then "falls" back and forms a black hole). Such stars would return very little chemically enriched material to the interstellar medium. It is difficult to estimate what fraction of massive stars that die in this way, but it is probably small.


Story Source:

The above story is based on materials provided by University of Copenhagen. Note: Materials may be edited for content and length.


Cite This Page:

University of Copenhagen. "New Type Of Massive Stellar Death." ScienceDaily. ScienceDaily, 24 December 2006. <www.sciencedaily.com/releases/2006/12/061221075003.htm>.
University of Copenhagen. (2006, December 24). New Type Of Massive Stellar Death. ScienceDaily. Retrieved September 17, 2014 from www.sciencedaily.com/releases/2006/12/061221075003.htm
University of Copenhagen. "New Type Of Massive Stellar Death." ScienceDaily. www.sciencedaily.com/releases/2006/12/061221075003.htm (accessed September 17, 2014).

Share This



More Space & Time News

Wednesday, September 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

East Coast Treated To Rare Meteor Sighting

East Coast Treated To Rare Meteor Sighting

Newsy (Sep. 16, 2014) — Numerous residents along the East Coast reported seeing a bright meteor flash through the sky Sunday night. Video provided by Newsy
Powered by NewsLook.com
Space Race Pits Bezos Vs Musk

Space Race Pits Bezos Vs Musk

Reuters - Business Video Online (Sep. 16, 2014) — Amazon CEO Jeff Bezos' startup will team up with Boeing and Lockheed to develop rocket engines as Elon Musk races to have his rockets certified. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
NASA Picks Boeing and SpaceX to Ferry Astronauts

NASA Picks Boeing and SpaceX to Ferry Astronauts

AP (Sep. 16, 2014) — NASA is a giant step closer to launching Americans again from U.S. soil. It has announced it has picked Boeing and SpaceX to transport astronauts to the International Space Station in the next few years. (Sept. 16) Video provided by AP
Powered by NewsLook.com
NASA to Resume Human Space Flight, Focus on Mars

NASA to Resume Human Space Flight, Focus on Mars

Reuters - US Online Video (Sep. 16, 2014) — NASA awards contracts to Boeing and SpaceX to ferry astronauts to the international space station, saying the move will allow the space agency to focus on more ambitious missions like sending humans to Mars. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

    Technology News



    Save/Print:
    Share:  

    Free Subscriptions


    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile


    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?


    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile iPhone Android Web
    Follow Facebook Twitter Google+
    Subscribe RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins